This application requests funds to continue longer-term follow up of outcomes and investigate maintenance of weight in a previously funded comparative effectiveness clinical trial (NIH# RC1DK086037) comparing surgical and medical treatments for Type 2 diabetes in lower BMI subjects. The initial study is the first successfully completed randomized feasibility and early outcomes trial to compare gastric bypass, gastric banding, and a structured weight loss program induced by diet and increased physical activity for the treatment of Type 2 diabetes mellitus (T2DM) in moderately obese patients with BMIs between 30 and 40 kg/m2. The primary aim of this proposal is to continue longer-term follow up of outcomes in a unique cohort of 60 total randomized subjects with Class I and II obesity that underwent intervention in one of three arms; gastric bypass, gastric banding, and a structured weight loss program. The outcomes of interest are measured at one year follow-up in the originally funded study, and will be extended to subsequent annual visits over 3 years. These measures include evaluation of diabetes resolution, change in metabolic parameters, body composition, physical activity, and several psychosocial measures. A secondary aim is to investigate the feasibility and importance of the initiation of a structured low level lifestyle intervention administered to all three treatment groups on weight maintenance over the longer-term follow up. Finally, longer-term data from this extension of the first randomized cohort of its type will fill an important knowledge gap and guide future studies. PUBLIC HEALTH RELEVANCE: Diabetes and obesity are a parallel world-wide epidemic. The best treatment for adult onset diabetes in people that are also obese is not fully understood. This study will compare how and why adult onset diabetes improves following three different types of treatment. Some patients will undergo intensive coaching to make diet and exercise changes in their lives to induce weight loss. Other patients will undergo two different surgical procedures; gastric bypass and gastric banding for weight loss. All of the subjects/patients in each of the three groups will be followed every year for three years to see how their diabetes and other measures of health status like risk for heart disease and measures of satisfaction may improve or change. Understanding more clearly the impact of bariatric surgery compared to a non-surgical, intensive lifestyle intervention for the treatment of diabetes in the setting of obesty will have a major impact on both the science and public health for the communities of obese and diabetic patients in this country and worldwide.